Process for converting petroleum oil



Feb. 10, 1931. W.IR. HOWARD PROCESS FOR CONVERTING PETROLEUM OIL Original Filed Dec. 27, 1921 L INVETOR.

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Patented Feb. 10, 1931 UNITED STATES PATENT OFFICE WILLIAM R. HOWARD, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TO UNI- VERSAL OIL PRODUCTS COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF SOUTH DAKOTA PROCESS FOR CONVERTING PETROLEUM OIL Original application flied December 27, 1921, Serial 110. 525,094. Divided and this application flied March 4, 1927. Serial No. 172,885.

This application is a division of my application Serial Number 525,094, filed December 27, 1921.

This invention relates to a process for converting petroleum oil and refers more particularlyto a process in which hydrocarbon oil is relieved of its lower boiling point fractions which are vaporized and condensed separately as distillate. The invention has to do with the treatment of oils in a still in which the oil is mechanically circulated in order that a more thorough and uniform treatment will be produced and the free carbon which; is separated out during conversion will be kept in suspension due to the circulation and agitation of the oil during treatment. A further feature of the invention is the returning and separately retreating of the reflux condensate in a separate closed still mounted in go the conversion chamber or retort.

The single figure is a side elevational view of the apparatus with parts broken away and parts in section to show the details of construction. In operation the oil is introduced from storage through the line 1 controlled by valves 2 and 3 and is charged by means of pump 4 through the line 5 regulated by a valve 6 to the still 7. This still is mounted above a furnace 8. The oil in the still is 3 raised to a temperature at which substantial conversion of the oil takes place. Durmg this conversion a pressure of the generated vapors is maintained upon the oil body in the still or retort 7. Within the still is mounted upon small standards 9 and open at both ends into a hollow cylinder 10 in both ends of which are positioned propellers 11 which are mounted upon the shafts 12 supported instufling box bearings 13 in each end of the still. On the outer extremities of the shafts 12 are pulleys 14 which are driven from any suitable source of power to rotate the propellers within the hollow cylinder so that an oil circulation will be produced within the cylinder in the direction of the arrows. The oil being introduced into the bottom of the still through the line 5 tends to sweep along the bottom or thehottest portion of the still or retort beneath the hollow ended cylinder 10. It is picked up by the circulation caused by the propeller blades at the opposite end of the retort and cross through the open ended cylinder, thus being thoroughlyintermixed in the oil body and kept in rapid circulation during heating. From time to time or continuously, according to the rate of reaction, the heavier or residuum oil may be drawn off through the line 15 controlled by a valve 16. The vapors evolved in the retort pass off through the line 17 controlled by a valve-18 and are introduced into a small dome 19 formed in the bottom of the hollow cylinder by means of the upturned end of the pipe 17 which is doubled back, into the bottom of the retort, and terminates in an upstanding nozzle 20. The vapors are thus forced to pass through the oil body'which will stand at a given level in the vapor line 21 which connects to thetcp of the dome 19. The vapors from the nozzle proceed through the vapor line up through the trap 22 formed therein and thence through the line 23 to the refluxing tower 24 where the reflux condensate is separated from the vapors, the uncondensed vapors passing off to the condenser 25 and thence to the receiver 26 where they are collected as liquid distillate. The reflux condensate which is separated out in the vapor line 23 will gravitate back and collect in the closed still 27 through lines 28 and 29, the trap 22 preventing any of the condensate from returning to the still 7. The condensate collecting in the reflux still 27 will be further converted, the vapors passing oif through the line 28, and any excess unvaporized oil being pumped from the still 27 by means of the suction pump 30 and connecting lines 31 and 32 to the still 33 which is mounted above the furnace 34. This still is supplied both from the reflux still 27 mounted in the larger retort 7 and also from the dephlegmator by means of a draw-ofl' line 35 controlled by a valve 36. In the still 33 the returned condensate which is of a more refractory character, is subjected to temperature and pressure conditions suflicient to produce further conversion, the vapors evolved therein, rising through the line 37 controlled by a valve 38, and combining with the vapors The agitation and circulation of the oil during treatment in the retort or still 7 revents any appreciable assimulation of ree carbon upon the bottom of the still and permits the operating of the a paratus for a considerably longer period 0 time.

A second feature of importance and one that has a substantial effect upon the character of the vapors which pass off is the fact that the vapors before rising into the vapor line, must pass through the oil body thus relieving said vapors of certain deleterious substances by the purifying treatment exerted thereon by the liquid oil and serving to keep the vapors at a very hot and constant temperature so that certain vaporized ends will not tend to condense in the still.

The advantage of returning and separately retreating the reflux condensate, relieves the still of retreating an oil which is objectionable due to the fact that it is more diflicult to crack upon retreatment than the raw oil which is being charged to the still. To retreat suchoil it is necessary to increase the temperature conditions to a point where conditions of conversion in the main body of the oil are increased to an objectionable state.

An increase of the temperature conditions necessary to produce conversion in this reflux condensate will cause an objectionable amount of free carbon to be separated from the raw oil charge, while where the oil is treated separately as in the hereinbefore explained process, the temperatures in the main still may be maintained more uniform;

A further advantage of the process is the fact that by returning the reflux to a separate retort for retreatment, the main oil charge loses but a small portion of its viscosity and therefore is more desirable for lubricating stock. Vi /hen the refluxed condensate is returned and mixed with the stock it tends to reduce the gravity or have a cutting-back effect which reduces materially its lubricating properties and makes it less desirable to be treated later for lubricating oil. By treating heat containing gas oil of approximately 30 to 32 B. under a pressure ranging from 100 to 200 pounds and temperatures 750 to 900 in the heating zone, a hi h grade distillate of from 40 to 60% of t e oil charge may be obtained, having a gravity of from 48 to 52 B.

I claim as my invention:

1. A process of hydrocarbon oil conversion which consists in maintaining a body of oil at a cracking temperature under superatmospheric pressure in a zone of vapor evolution, taking off vapors therefrom and subjecti ng them to primary reflux condensation, and returning the reflux condensate to the zone of vapor evolution wherein it is heated to the temperature prevailing therein, out of physical contact with the constituents therein, and vaporsare evolved from the reflux condensate, combining the vapors uncondensed by said reflux condensation with the vapors evolved from the returned reflux condensate and subjecting the combinedvapors to secondary dephlegmation and condensation as the product of the process.

2. A process of hydrocarbon oil conversion which consists in maintaining a body of oil at a cracking temperature under superatmospheric pressure in a zone of vapor evolution, taking off vaporstherefrom and subjecting them to primary reflux condensation, and returning the reflux condensate to the ,zone of vapor evolution wherein it is heated to the temperature prevailing therein, out

of physical contact with the constituents therein, and vapors are evolved from the reflux condensate, combining the vapor uncondensed by said reflux condensation with the vapors evolved from the returned reflux condensate and subjecting the combined vapors to secondary dephlegmation and condensation as the product of the process, passing unvaporized constituents: o the reheated primary reflux condensate to an independent still, returning the secondary reflux condensate to the same independent still, and heating the combined reflux condensate to a crackin temperature higher than the original cracking heat. 4

3. A \process of hydrocarbon oil conversion which consists in maintaining a body of oil at a cracking temperature under superatmospheric pressure in a zone of vapor evolution, taking off vapors therefrom and subjecting them to primary reflux condensation, and returning the reflux condensate to the zone of vapor evolution wherein it is heated to the temperature prevailing therein, out of physical contact with the constituents therein, and vapors are evolved from the reflux condensate, combining the vapors uncon-v densed by said reflux condensation with the densate and subjecting the combined vapors to secondary dephlegmation and condensation as the product of the process, passing unvaporized constituents of the reheated rimary reflux condensate to an indepen ent still, returning the secondary reflux con densate to the same inde nd'ent still, and heating the combined re ux condensate to a cracking temperature higher than the original cracking heat, and introducing a part of the 'chargin oil for the process to said independent sti l.

4; A process of hydrocarbon oil conversion which consists in maintaining a body of oil 115 vapors evolved from the returned reflux con-.

at a cracking temperature under superatmosphenc pressure in a zone of vapor evolution, taking off vapors therefrom, injecting them into the body of oil undergoing treatment in said zone of vaporization to permit the vapors to pass upwardly therethrough to relieve them of deleterious substances, preventing the returned vapors from combining with the primarily evolved vapors, withdrawing the returned vapors after passage through the liquid oil and subjecting them to primar reflux condensation, and returning the re ux condensate to the zone of vapor evolution wherein it is heated to the tem-,

perature prevailing therein, out of physical contact with the constituents therein, and vapors are evolved from the reflux condensate, combining the vapors uncondensed by said reflux condensation with the vapors evolved from the returned reflux condensate and sub* jecting the combined vapors to secondary dephlegmation and condensation as the product of the process.

' WILLIAM R. HOWARD. 

